1. Field of the Invention
This invention relates to a multichamber cuvette and relates more particularly to such cuvette which, while not limited thereto, is especially useful in quantitative analysis by optical density of a constituent of body fluids such as blood or urine for example.
2. Prior Art
Brown et al. U.S. Pat. No. 3,691,017 and Mailen U.S. Pat. No. 3,795,451 are typical of the prior art. Brown et al. disclosed a multichamber cuvette for analysis of a constituent of interest in body fluids by an optical density determination in an automated manner. It was disclosed by Brown et al. that a reaction may be measured in the cuvette at one point in its duration or at its end point or a reaction in the cuvette may be temperature-and-time dependent and of the type measured over a period of time to indicate the quantity of the constituent of interest by the rate of the reaction. In accordance with Brown et al., in such kinetic or rate reaction analysis of an enzyme, a trigger or key reactant component, initially located in a first chamber in restricted communication with a second chamber through a passageway, was of a substrate of an enzymatically catalyzed reaction with a reactant component in the second chamber. After a solvent medium had been introduced in the chambers to reconstitute the reagents previously in lyophilized form therein, a liquid sample comprising the catalyzing enzyme was introduced into the second chamber prior to forceful injection thereinto through the aforementioned passageway of the key substance for the reaction to proceed under temperature-controlled conditions.
The cuvette was found to have many drawbacks in practice adversely affecting analysis among which, of a more serious type, were that the cuvette had a lower passageway interconnecting the chambers through which a diluent such as water flowed on reconstitution of the lyophilized reagents. In accordance with Brown et al., only a single diluent injection was utilized to reconstitute the different reagents in both chambers. This injection was made into the second chamber for partial retention therein and partial flow therethrough and through the passageway into the first chamber for retention in the latter, resulting in a high degree of risk of comingling the reagents prior to intentional mixing thereof. This construction and use of the cuvette enabled a small quantity of one of the liquid reagents in one chamber to migrate into and commence reaction with the other liquid reagent in the other chamber during the period of time when it was desired to maintain the last-mentioned liquids in complete isolation from one another, as during incubation, to prevent their premature reaction with one another. It was found that migration by diffusion of only 3% of the reconstituted aforementioned trigger or key component into the aforementioned second chamber was sufficient to invalidate an analysis. Such reagent migration might be occasioned by jarring the cuvette, for example. In view of the foregoing, it will be appreciated that the aforementioned reconstituted reagents in the two chambers of the cuvette were in liquid interfacing relationship in the area of the aforementioned passageway prior to intentional mixing of the reagents, and that such reagent migration discussed above was in fact was likely unless the cuvette was handled with extreme care.
The Mailen U.S. Pat. No. 3,795,451 disclosed a rotor for mixing sample and reagent liquids loaded thereinto for use in a photometric analyzer of the rotary sample-analysis cuvette type. Inner and outer concentric arrays of loading cavities were disposed within the rotor on a one to one basis centripetal to an array of sample analysis cuvettes. Liquid communication was provided by capillary-sized passageways between the respective sample, reagent and analysis cavities and cuvettes upon rotation of the rotor, while intercontact of the liquids in the respective cavities was prevented under static loading conditions. The aforementioned respective passageways between the inner and outer cavities were each provided with an air lock in the form of a bubble trap under static conditions.
The present invention overcomes difficulties in the prior art.